What is Irish Set Dance?
The set dance is a fast dance often accompanied by rhythmic tap steps. In general, the foot is moved relatively flat, jumps etc. are avoided.
As a rule, four couples line up in a square. All eight dancers involved as well as the dance itself is called a set. The dance then consists of a specific choreographic sequence of three to nine dance figures (four to six are usual) with a short break in between. In the set, the couple with their backs to the band (music) is traditionally referred to as first tops and the opposite couple as second tops. Usually the couple to the left of the First Tops are referred to as First Sides, and the couple opposite them as Second Sides. These terms are also used outside Ireland.
Set dancing is done to reels, jigs, polkas, hornpipes, and less often to mazurkas.
Here is a video to illustrate
The Claddagh Set